Frankly, a little apprehensive about adding this as a true FKT as it was not the intention at the time of running. But in the spirit of advancing faster times, I'll add this to the list. The stated route is NE to SW from E. Rosebud Lake to the Clarks Fork TH in Cooke City, but all listed FKT's are the reverse/easier route beginning from the Clark Forks TH. My route traveled the same from the Clarks Fork TH NE to E. Rosebud Lake. The primary goal of the traverse was to quite literally run a shuttle to facilitate a family backpacking trip from E. Rosebud Lake in the subsequent days. Monday, 8/3, drove from E. Rosebud to the Clark Fork Trailhead and set off at 11:07a. Some ominous clouds, wind, and rain at the start which quickly gave way to a hot afternoon especially dropping into the eastside. Scoped campsites along the way for subsequent return trip. Twisted ankle at Lake of the Falls requiring some walking beyond that point. Arrived at E. Rosebud with 4:54:27 and 27.56 miles on the watch. Departed 8:30a Tuesday for 3 day backpacking trip back to Clarks Fork TH.
Straightforward trail that has no navigational challenges except for the first 100 yds from the Clarks Fork TH. Plenty of flowing creeks to stay hydrated and huckleberries to stay fueled along the way. SW to NE has less climbing than the alternative direction and the trail is indeed a beaten path. Would expect this time to be in the low 4 hour mark.